Sn= series 1 to infinity (n!)^n/(n^n)^2. It is C/D?
Explanation:
To evaluate the series Sn = ∑(n!)^n/(n^n)^2, we need to analyze the behavior of the individual terms and determine if the series converges or diverges.
Step 1: Simplifying the terms
Let's simplify the terms of the series before proceeding further.
The term (n!)^n can be expressed as (n!)^n = n^n * n! = n^n * n * (n-1) * (n-2) * ... * 3 * 2 * 1.
Similarly, (n^n)^2 can be expressed as (n^n)^2 = n^2n = n^(2n).
Substituting these values into the series, we get:
Sn = ∑(n^n * n!)/(n^(2n))
Step 2: Analyzing the terms
To determine if the series converges or diverges, we can use the ratio test. Let's apply the ratio test to the series Sn.
Let's define the ratio Rn = [(n+1)^(n+1) * (n+1)!]/[(n^n * n!)] * [(n^(2n))/(n^(2n))].
Simplifying Rn, we get:
Rn = [(n+1)^(n+1) * (n+1)!]/[n^n * n!] * [n^(2n)/(n^(2n))] = [(n+1)^(n+1) * (n+1)!]/[n^n * n! * n^(2n)].
Step 3: Applying the ratio test
To apply the ratio test, we take the limit as n approaches infinity of the absolute value of Rn.
Let's calculate the limit:
lim(n→∞) |Rn| = lim(n→∞) |[(n+1)^(n+1) * (n+1)!]/[n^n * n! * n^(2n)]|.
Simplifying the expression, we get:
lim(n→∞) |Rn| = lim(n→∞) |[(n+1)^(n+1)]/[n^n * n^(2n)] * [(n+1)!]/[n!]|.
Using the properties of limits and the fact that n! = n * (n-1)!, we can simplify the expression further:
lim(n→∞) |Rn| = lim(n→∞) |(n+1)/n * (n+1)^n * (n+1)/n^(2n)|.
Step 4: Evaluating the limit
Let's evaluate the limit using the properties of limits.
lim(n→∞) |Rn| = lim(n→∞) |(n+1)/n| * lim(n→∞) |(n+1)^n| * lim(n→∞) |(n+1)/n^(2n)|.
Using the limit definition of e^x, we know that lim(n→∞) (1 + 1/n)^n =